utils/drops: update Drop to support Utils.deep_merge_hashes

Fixes #4287

lib/jekyll/drops/drop.rb

@@ -71,6 +71,18 @@ module Jekyll
         end
       end
 
+      # Generates a list of strings which correspond to content getter
+      # methods.
+      #
+      # Returns an Array of strings which represent method-specific keys.
+      def content_methods
+        @content_methods ||= (
+          self.class.instance_methods(false) - NON_CONTENT_METHODS
+        ).map(&:to_s).reject do |method|
+          method.end_with?("=")
+        end
+      end
+
       # Generates a list of keys with user content as their values.
       # This gathers up the Drop methods and keys of the mutations and
       # underlying data hashes and performs a set union to ensure a list
@@ -78,7 +90,7 @@ module Jekyll
       #
       # Returns an Array of unique keys for content for the Drop.
       def keys
-        ((self.class.instance_methods(false) - NON_CONTENT_METHODS).map(&:to_s) |
+        (content_methods |
           @mutations.keys |
           fallback_data.keys).flatten
       end
@@ -102,6 +114,15 @@ module Jekyll
         JSON.pretty_generate to_h
       end
 
+      # Collects all the keys and passes each to the block in turn.
+      #
+      # block - a block which accepts one argument, the key
+      #
+      # Returns nothing.
+      def each_key(&block)
+        keys.each(&block)
+      end
+
     end
   end
 end

lib/jekyll/drops/unified_payload_drop.rb

@@ -3,21 +3,17 @@
 module Jekyll
   module Drops
     class UnifiedPayloadDrop < Drop
-      mutable false
+      mutable true
 
       attr_accessor :page, :layout, :content, :paginator
       attr_accessor :highlighter_prefix, :highlighter_suffix
 
-      def initialize(site)
-        @site = site
-      end
-
       def jekyll
         JekyllDrop.global
       end
 
       def site
-        @site_drop ||= SiteDrop.new(@site)
+        @site_drop ||= SiteDrop.new(@obj)
       end
 
       private

lib/jekyll/utils.rb

@@ -31,7 +31,8 @@ module Jekyll
     # Thanks to whoever made it.
     def deep_merge_hashes!(target, overwrite)
       overwrite.each_key do |key|
-        if overwrite[key].is_a? Hash and target[key].is_a? Hash
+        if (overwrite[key].is_a?(Hash) or overwrite[key].is_a?(Drops::Drop)) and
+            (target[key].is_a?(Hash) or target[key].is_a?(Drops::Drop))
           target[key] = Utils.deep_merge_hashes(target[key], overwrite[key])
           next
         end
@@ -39,7 +40,7 @@ module Jekyll
         target[key] = overwrite[key]
       end
 
-      if target.default_proc.nil?
+      if target.respond_to?(:default_proc) && overwrite.respond_to?(:default_proc) && target.default_proc.nil?
         target.default_proc = overwrite.default_proc
       end
 

test/test_utils.rb

@@ -4,15 +4,25 @@ class TestUtils < JekyllUnitTest
   context "The \`Utils.deep_merge_hashes\` method" do
     setup do
       clear_dest
-      config = Jekyll::Configuration::DEFAULTS.merge({'source' => source_dir, 'destination' => dest_dir})
-
-      @site = fixture_site(config)
+      @site = fixture_site
       @site.process
     end
 
-    should "merge a page into the site" do
+    should "merge a drop into a hash" do
       data = {"page" => {}}
-      assert Utils.deep_merge_hashes(data, @site.site_payload)
+      merged = Utils.deep_merge_hashes(data, @site.site_payload)
+      assert merged.is_a? Hash
+      assert merged["site"].is_a? Drops::SiteDrop
+      assert_equal data["page"], {}
+    end
+
+    should "merge a hash into a drop" do
+      data = {"page" => {}}
+      assert_nil @site.site_payload["page"]
+      merged = Utils.deep_merge_hashes(@site.site_payload, data)
+      assert merged.is_a? Drops::UnifiedPayloadDrop
+      assert merged["site"].is_a? Drops::SiteDrop
+      assert_equal data["page"], {}
     end
   end